Identification of lipid subclasses by MALDI-MS in blood and follicular fluid of cows supplemented with different vegetable oils

Nutrition has major effects on reproductive processes in cattle. Vegetable oils are major sources of polyunsaturated (PUFA) fatty acids, whose effects are related to the ability to modulate the metabolism of arachidonic acid and prostaglandin, to increase circulating levels of insulin -like growth factor (IGF-I) and to promote the increase of plasma cholesterol which is a substrate for the synthesis of steroid hormones such as progesterone (P4) and estrogen (E2). The aim of this study was to identify different lipid classes in blood and follicular fluid of animals subjected to supplementation nutritional with sunflower oil, soybean oil or canola through the technique of direct analysis assisted laser desorption matrix (MALDI - MS). The animals were fed their respective diets for 70 days. The control group received the same diet of others, without the addition of vegetable oil. Weekly blood samples and follicular fluid were collected. The identification of the lipids in the samples was performed using MALDI -TOF MS. In females supplemented with canola oil lipid subclasses conjugated steroids (ST) and phosphatidylserines (PS) have been identified in follicular fluid. The animals supplemented with sunflower group showed conjugated steroid (ST) in blood serum and phosphatidylinositol conjugated to ceramides (Cer - PI) and phosphatidylserines (PS) in follicular fluid. Finally, the group receiving soybean oil as a supplement, the compounds phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI) were identified in the blood serum and no lipid subclass was identified in follicular fluid of these animals in the control group. The separation between the control and the treatments was observed and identified substances, mostly accounted for constituent membrane lipids (phosphatidylserine - PS, phosphatidylethanolamine - PE), intracellular second messengers (phosphatidylinositol - PI) or conjugated steroids (ST), which are precursors of steroid hormones such as progesterone and estradiol. It is concluded that canola and sunflower oils were capable of altering the lipid composition of intra - follicular environment which may influence the quality of the oocytes formed. Changes in steroid conjugates observed in the blood serum of animals supplemented with sunflower oil may contribute to an increased production of steroid hormones by increasing further the steroidogenic process. Soybean oil induced changes in the blood profile, but these were not reflected in changes in intra- follicular environment.